The temperature‐sensitive yeast DNA primase mutant pri1‐M4 fails to execute an early step of DNA replication and exhibits a dominant, allele‐specific sensitivity to DNA‐damaging agents. pri1‐M4 is defective in slowing down the rate of S phase progression and partially delaying the G1–S transition in response to DNA damage. Conversely, the G2 DNA damage response and the S–M checkpoint coupling completion of DNA replication to mitosis are unaffected. The signal transduction pathway leading to Rad53p phosphorylation induced by DNA damage is proficient in pri1‐M4, and cell cycle delay caused by Rad53p overexpression is counteracted by the pri1‐M4 mutation. Altogether, our results suggest that DNA primase plays an essential role in a subset of the Rad53p‐dependent checkpoint pathways controlling cell cycle progression in response to DNA damage.
- Received June 13, 1996.
- Revision received October 31, 1996.
- Copyright © 1997 European Molecular Biology Organization